Separable attachment-plug.



' R. B. BENJAMIN. SEPARABLE ATTACHMENT PLUG.

' I APPLICATION FILED AUG.10, 1909. Lmfifimn Patented July m, 1914;

. I 2 SHEETS-SHEET 1. @1 25? Z fl {it 12 R. B. BENJAMIN. SEPARABLBATTACHMENT PLUG;

- v APPLICATION I'iLED AUG. 10, 1909- l ].@3 %5@ Patented July M, 11.9%

2 SHEETS-SHEET 2.

Improvements part of UNITED STATES PATENT OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO, ILL

INOIS, ASSIG-NOR TO BENJAMIN ELECTRIC MANUFACTURING COMPANY, OF CHICAGO,ILLINOIS, A CORPORATION OF ILLINOIS.

EPARAZBLEATTACHMENT-PLUG.

To all whom it may concern:

Be it known that I, REUBEN B. BENJAMIN, a citizen of the United States,residing at (.hicago, of Illinois, have invented new and useful inSeparable Attachment- Plu gs, of which the following-is a full, clear,concise; and exact description, reference being had to the accompanyingdrawing, forming a part of this specification.

This invention relates to improvements in separable attachment-plugs,the ob ect ot the invention being to provide a device in which the partwhich makes connection directly with the stationary socket may bereadily separated, when desired, from the part which carries the bindingterminals to which are secured the leading-out conductors, the devicebeing so constructed, however, that accidental separation is not likelyto occur unless an abnormal strain be placed upon the conductors, whenthe parts may separate in order to prevent damage being done to thedevice or the stationary socket, or the wires being torn loose from thebinding terminals of the. device.

Another object of the invention is to provide a device of this classwhich is so constructed that when it is desired to manually*separate"the two parts thereof without jarring the'iixture which carries thesocket with which connection is made this may be done by givinga slightrotation to the part which is grasped by the hand, this being the partwhich carries the binding screws and wires.

Heretofore, as separable attachment plugs have usually been constructed,the separation of the parts has been effected by simply withdrawing oneof the parts from the other with a straight pull. This has proven to beobjectionable in many instances as where the socket with whichconnection is made forms a chandelier carrying a number of lamps andshades therefor. When a direct pull is exerted to separate the parts theseparation is resisted for a time until the force exerted becomes greatenough to overcome the resistance of the clips or other parts which tendto hold the members of the plug together whereupon these membersseparate with a sudden jerk which is liable to cause damage to thechandelier, shades and the like. By the use of my invention thisdifficulty is overcome, it being possible Specification of LettersPatent.

in the county of Cook and State,

Patented July 14,1914.

-Application filed August 10, 1909. Serial No. 512,147.

to separate one part of the plug from the other without any undue forcebeing em-' ployed or vibration caused.

In the accomplishment of the above objects I provide a cap member. whichis arranged to be screwed into the stationary socket, which cap membercarries a side contactand an end contact arranged for engage ment withthe corresponding contacts of the socket. I'then provide a plug memberfrom which extend the leading-out wires, said plug member beingarranged'tobe inserted into the cap member and, when soinserted, to makeelectrical connection bet-ween certain contactscarried thereby and thecontacts of said cap member, the contacts of the plug being electricallyconnected with the binding terminals to which the wires are secured.Electrical connection is thus made between the wires and the contacts ofthe stationary socket. I also provide means whereby an abnormal strainexerted in a direction which would tend to cause the plug member to pullout of the cap member will not be resisted to such an extent as toprevent such separation, although any such strain as would ordinarily beplaced upon the device will be insufficient to cause the parts toseparate. The interlocking parts upon the two separable members arearranged to make connection when one of saidmembers is thrust directlyinto the other. After the parts have thusbecome locked togethersuflicient resistance to the separation of said parts is ofiered'toprevent the same from separating under ordinary conditions, as

above stated, but if a sh ht rotation is given plug member being forcedout of the cap member to some extent, thus insuring the parts remainingdetached from each other.

In the accompanying drawings, Figure 1 is a side elevational view of thedevice with the two separable members put together; Fig. 2 is abottom'plan view of the upper or cap member, or that member which isarranged to be inserted into a socket; Fig. 3 is a top *plan view of thelower or plug member; Fig. l is a bottom plan view of the plug member,the insulating cap which incloses the lower part of the same beingremoved; Fig. 5 is a longitudinal sectional view of the device with theseparable members connected to each other; Fig. 6 illustrates the devicering.

tion being taken on the line 7 -7 of Fig. 4:,

looking in the direction of the arrows; and Fig. 8 is a sectional viewof a portion of the plug member, the section being'taken on thel'ine 8-8 of Fig. 4, looking in the direction of the arrows.

in the several figures of the drawings, 10 is an-insulating base memberwhich occupies the upper portion and extends somewhat beyond the upperend of a. threaded metallic ring 11. Below the threaded part of the ringthe same is drawn in slightly at 12, the base 10 resting upon theshoulder formed by thus drawing in the material of the ringgandbeingfurtber held in place by the indented semicircular bosses 12 on theTo hold the base against upward movement in the ring the base is formedwith a pair of oppositely disposed cavities 13, the material of'the ringat its upper edge being turned over into these recesses at 14.Surrounding-the lower portion of the ring is an insulating sleeve 15,the latter being prevented from slipping off the lower end of thethreaded ring by forming the ring with ahead 16 at its lower edge andbeading the insulating sleeve at 17 so that the head on thering'oecupiesthe bead in the sleeve.

The lower'p'ortion of the insulating base is chambered out 'at 18. Fromthis chamber a' passage extends upward through the base and opens at theupper end of the latter.

A contact member comprising a strip 19,

which extends acrossthe upper end of the chamber in-the base and isprovided with a downwardly extending leg 20 at each of its ends, issecured inposition in the chamber by means of a hollow rivet 21 whichextends through the aperture of the base and is headed over at' itsupper end to form a center contact member for the device. When the capmember, which comprises the base and threaded ring, is screwed into asocket electrical connection is made by the threaded ring with thethreaded contact of the sm-ket" and by the contact member 21 with thecenter contact of the socket.

Thelower or plug member comprises an insulating base 21 made somewhatconeshapedand having a metallic ring 22 extending around its lower andlarger portion, this'ringbeing turned over inward upon a shoulder 23formed upon the base. The lower end of the ring 22 is drawn in under thebase 21 and then extends downward to formf a neck: 2 having screwthreads rolled. in the material thereof. A 'cap 25, whichinc'loses thethreaded part 24 of the is formed of insulating material and has a neckportion 26 which is exteriorly screw threaded and screws up into theneck 24. Between the upper edge of the cap 25 and the shoulder caused bydrawing in the material of the ring 22 under the base is arranged aninsulating ring 27 which extends laterally beyond the edge of the cap soas tobe readily grasped by the fingers of a person. Upon the lower endof the base there is formed a projecting hump 28 which extends down forashort distance into the neck 26 of the insulating cap 25. When theleading-out conductors are in posit-ion and the cap 25 is screwed up inplace the conductors are gripped between the inner wall ofthe upper endof the neck 26 and this hump 28, whereby the conductors are rin 22,

securely held and undue strain, which might otherwise be exerted uponthe binding screws to tear the conductors from the same, is avoided.

When the base 21 and the ring 22 carried thereby, which form theinsertible part of the device, are thrust into the lower end of the capportion. of the device electrical conuection is made between theinterior of the ring 11 and the exterior of the ring 22. To insure goodelectrical contact being made the ring 11 is provided with threeinwardly projecting bumps 30 which make rubbing contact with the ring22. A binding screw 31 is provided for making electrical connection ofone of the leading-out conductors with the ring '22. this binding screwbeing carried by a tonguex32 formed by cutting the ring 22 vertically ateach side of the screw' 31','the tongue being set back into a suitablerecess formed in the base 21. The screw 31 is provided with a nut 33located in the recess in the base, being prevented from rotating bythe-shape of the recess. A passage 34 extends from the under side of thebase up to the tongue 32, this passage being pro Theupper portion of thechamber 35 is en larged in diameter to receive a cup-shaped contactpiece 37. The contact piece 37 is held in posit-ion by a plate 38 whichis provided with apair of prongs 39, the latter being bent downward at aright angle with the body of .theplate and extendingthrough openings orpassages which lead down from the chamber 35. The lower ends 40 of theseprongs are turned outward and extend laterally into channels 41 in theunder side of the base. A-binding screw 38* screws into the pelled toopen.

. Within the other unlocks the device. 30 little efl'ort is required inrevolving the plug plate 38 and has its head sunk in the cupshapedcontact piece 37. An opening 37 is made in the contact piece 37 for thepassage of the second wire to the binding screw 38 after the same hasbeen brought up through the passage 36. The cup-shaped contact piece 37has its side walls bowed outward intermediate its top and bottonn thusbecoming an enlarged head which, when the lower or plug portion of thedevice is inserted into the upper or-cap portion thereof, is grippedupon oppositesides by the resilient, fingers 20 of. the contact piece 19carried by the cap portion. The lower ends ,of the contact 'fingers 20are inclined, inward and then outward so that when the parts are thrusttogether the contact fingers will be wedged apart to permit the head 37to pass therebetween. I The inwardly projecting heels 42 uponthe-contact fingers grip under the head 37 when the parts are puttogether, and thus hold the plug portion of the device locked to the capportlon.

The upper end of the base 21 of the plug portion is madeWedge-shaped,'being tapered off at each side of a line extending acrossthe axis, as clearly seen in Figs. 3, and 6. When the parts arethrusttoget-her, as illus trated in Fig. '5, the lower, outwardlyinclined portions of the contact fingers rest upon the inclined sides 43of the base 21 but arenqt prevented from firmly gripping the head 37.If, however, a slight rotation be given to the plug portion of thedevice, the inclined lower endsofthe spring fingers are caused to rideuthe inclines and are .com-

en the plug portion has beenrevolved far enough to carry the contactfingers nearly up to the highest points of the lnclines the lingers areopened sufficiently to release the head from their grasp, permitting theplug portion of the device to drop out of the cap portion. a f By thearrangement of a head upon the lower portion and resilient fingers uponthe upper portion arranged to grip under this head, there is afi'orded aform of lock which is impositive, .and whichthus permitsthe device to beseparated when an undue pull-- ing strain is exerted upon the parts,this look being, however, sufliciently positive in its action togive-all needed security against separation under normal conditions. By

theprovision of the wedge-shaped portion upon the upper end of the plugadjacent the head means are provided whereby a' slight rotation (at mosta movement equal to onefourth of a complete revolution) of one. partVery member to separate the members, thus but little twisting effect isimparted to the upperi portion of the device. When the parts are broughtto the proper angular relation to each other the plug portion isautomatically thrust out by the resilient fingers, thus not only is nodirect pull upon the plug required when the device is to be manuallyseparated, but it is, rendered impossible to give such a pull to thedevice if the plug is turned to the unlocking position. It will thus beseen that in unlocking one part from the other the action is exceedinglysmooth, there being complete freedom from the sudden breaking away ofone part from the other, with the consequent tendency to a reaction,which is common'to, other separable attachment plugs, and which reactionresults in damage to fixtures, shades and the like,

7 Having thus described my invention, what ters Patent, is:

1. An attachment plug comprising two separable members, one of saidmembers having contacts for cotiperation with the contacts of a socket,and the other member having binding terminals associated therewith;means for locking said members together with said contacts in electricalcommunication with said binding terminals, said locking means beingreleasable upon the application of a predetermined force to saidbinding-terminal-carrying-member in a direct pull, and manually operablemeans for releasing said locking means and at the same time forcing'saidmembers apart.

2. An attachment plug comprising two separable members, one of saidmembers having contacts for cooperation with the with; means for lockingsaid members tomunication with said binding terminals, said lockingmeans being releasable upon the application of a predetermined force tosaid binding-terrninal-carrying-member in a direct; pull; and means forreleasing said looking means and at the same time forcing said membersapart, upon rotation of one of said members with respect to the other.

3. In an attachment plug, the combination of a pair of separablemembers, one of said members having contacts for cooperatien with thecontacts of a socket, binding terminalscarried by the other of saidmembers, means for looking said memberstogethe'r with said contacts andbinding terminals in electrical communication with each other upon adirect thrust of one of said members toward the other, said lockingmeans being releasable upon the application of a predetermined force tosaid binding-terminal-carrying-member in a direct pull, and means the.other. g

4.- An attachment plug comprising two separable members, one ofsaidmembers hecontacts of a socket, and the other member gether withsaid contacts in electrical com for releasing said locking mean uponrota-- *tion of one of said members with respect to 'ing provided with acenter contact and an I claim as new and desire to'secureby Letoutercontact ,for engaging the center contact and the threaded contactrespectively of a socket, and the other of said members hav saidlast-named member being rotated.

An attachment plug comprising twoI separable members, one of saidmembers b' ing provided with a center contact and an outer contact forengaging the center cond tact and the threaded contact respectively: ofa .socket, and the other of said members, having binding terminalsassociated there-: with, said second-named member being formed with acam surface; a contact head carried by said second-named member andelectrically connected with one of the binding terminals thereof; and aspring clip carried by said first-named member and adapted to receivesaid head when said members are thrust together, said clip beingelectri' cally connected with one of the contacts of said first-namedmember, and said clip being arranged to be engaged by the cam surface ofsz'zid second-named member and'o pened. thereby upon said second-namedmember being rotated.

(i. In a. separable attachment plug, the combination of a pair oftelescoping members, external contacts carried by one of said members,binding terminals carried by the other of said members and arranged tobe brought into electrical connection with said external contacts whensaid members are thrust together, one of said members- .having anincline formed thereon, a' head extending beyond said incliile, andresilient fingers carried by the other member and,

1,103,2gsd

thereby forced outof engagement with said head.

7. A separable attachment plug comprising' a pair" of telescopingmembers, one of said members being provided with a center contact and anouter contact for engaging the center contact and the threaded'contactrespectively of a socket, and the otheri'of said members having bindingterminalsassoclated therewith, said second-namedmeIIlher having anincline formed thereon; a

contact head carried by said second-named member and electricallyconnected with one of the binding terminals thereof;' and resilientfingers carried by said first-named member and electrically connectedwith one of the contacts thereof, said fingers being arranged to rideupon said incline when said second-named member is rotated and to besaid contact-sleeve at the indented portion thereof. y

In Witness whereof, I have hereunto subscribed my name in the presenceof two witnesses.

REUBENB. ENJ MIN; Witnesses: 4

\OHARLES G. Corn,

QHAs. L. HOPKINS,

